The present invention generally relates to electrical production. More particularly, the invention provides a method and resulting device for fabricating an electret device having a liquid dielectric entity for generation of electrical power. Merely by way of example, the electret device has been fabricated using a patterning process including micromachining processes. But it would be recognized that other processes such as molding, casting, laser ablation, direct printing, etc. can also be used.
Electromagnetic generators have been used to supply power to a variety of applications. Extremely large power generators exist, such as those providing power using movement of water from large rivers that have been controlled by dams. As merely an example, Hoover Dam produces electricity for Los Angeles, Calif., United States of America. Alternatively, electromagnetic generators can be small to supply power to operate certain electronic functions on automobiles, home appliances, and personal appliances. Other types of generators also exist.
As merely an example, one type of electromagnetic generator is a direct current (“DC”) generator. Often times, the DC generator uses a rotating member that converts mechanical kinetic energy into electrical energy. Such conversion is provided by a rotating member called an armature, which carries conductors. The rotating member is within a magnetic field. To generate power, mechanical force is applied to the armature, which rotates within the magnetic field. Here, the armature turns about an axis which extends along the magnetic field. The rotation or twist of the armature within the field generates electric energy including voltage and current. The voltage and current are delivered through external load circuitry. Power generation from electromagnetic generators comes from what we understand as electromagnetic forces. Further details of the theory and operation of the electromagnetic generator can be found in The Bureau of Naval Personal, BASIC ELECTRICITY, Second Revised and Enlarged Edition, Dover Publications, Inc., New York (1969), among other sources.
Although highly effective for certain applications, electromagnetic generators have limitations as they become smaller and smaller. As merely an example, electromagnetic generators have been ineffective for providing power for applications having a form factor of less than one cubic centimeter. Conventional electromagnetic generators often cannot provide enough power as the size of the armature becomes less than an inch to operate many modern electronic devices such as cell phones, personal digital assistants, pagers, pace makers, and the like.
As merely an example, one of the smallest known commercial electromagnetic generators are being used has been developed by Seiko's Kinetic™ series watches of Seiko Corporation (herein “Seiko”) of the United States of America. The peak power output from these generators is less than 40 microwatts, and not sufficient for continuous operation of the watch hands. To emphasize the problems, Seiko must often use a backup system inside their watches as well as many power saving techniques to keep time. Functionality of the watch is sacrificed due to the lack of a sufficient power supply. Accordingly, modern electronic devices still rely upon power from chemical power sources such as batteries, which often have a fixed life, are difficult to charge, and cumbersome.
Accordingly, electret generators are proposed to meet the needs of small scale electricity generation for portable and remote location electronics. These electret generators rely upon electromotive force that is purely electric, rather than electromagnetic force used by conventional electromagnetic generators. Electret generator theory and experiments have been reported by O. D. Jefimenko, IEEE Trans. Ind. Appl., Vol. IA-I4, pp. 537-540, 1978 and by Y. Tada, IEEE Trans. Elect. Insul. EI-21, 1986, pp. 457-464. An electret generator with a radius of 45 mm was studied by Y. Tada, Jpn. J. Appl. Phys., Vol. 31, Part 1, No. 3, 1992, pp. 846-851. Here, a maximum reported power output from an electret generator was 1.02 mW. Unfortunately, conventional electret generators still lack a capability of becoming smaller and more effective and have not seen any commercial use. These and other limitations are described in further detail throughout the present specification and more particularly below.
From the above, it is seen that improved techniques for power generation is highly desirable.